This study is part of the International Vaccine Institute's (IVI's) typhoid Vi demonstration project that aims to accelerate the rational introduction of Vi vaccines in typhoid endemic countries. The purpose of this study is to determine the effectiveness of the Vi vaccine following a mass typhoid immunization campaign in an endemic area in Karachi, Pakistan. The cost-effectiveness of Vi vaccination and the logistic feasibility of a mass typhoid immunization campaign will also be evaluated.

Typhoid fever is a major cause of morbidity worldwide. The disease predominantly affects school-aged children, is more prevalent in urban areas, may last for several weeks and can lead to serious complications. Management of this disease is further complicated by the emergence of multi-drug resistant strains. Vaccination of high risk populations is considered the most promising strategy for the control of typhoid fever. The Vi polysaccharide vaccine has been targeted for accelerated introduction into public health programs due to the following reasons: it has been shown to have consistent efficacy results even in areas of high typhoid incidence; is given as a single dose; lacks patent protection and requires less strict cold chain requirements. A cluster-randomized trial involving the Vi polysaccharide vaccine and an active control (hepatitis A) was designed to determine the effectiveness and the feasibility of providing Vi vaccine under actual programmatic conditions in 3 urban slums in Pakistan. The vaccines used in this study are internationally produced and locally licensed. A complimentary, targeted, basic typhoid prevention health education program for the entire population at the initiation of the project will be provided and the actual Vi-demonstration project will be preceded by a 12-month typhoid surveillance activity.

Secondary objectives of this trial are:

To monitor the adverse events following a routine Vi mass vaccination campaign;

To assess the knowledge, attitudes, beliefs and practices among parents and health care providers regarding typhoid illness, treatment and prevention; and

To study typhoid fever risk factors in the population.

A nested, prospective matched case-control study is included in the trial in order to study typhoid risk factors among children in Karachi.

Eligibility

Ages Eligible for Study:

2 Years to 16 Years

Genders Eligible for Study:

Both

Accepts Healthy Volunteers:

Yes

Criteria

Inclusion Criteria:

Registered in the project census

Age: 2-16 years

Exclusion Criteria:

Fever >37.5 degrees Celsius, axillary

Pregnancy

Lactating

Contacts and Locations

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study.
To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below.
For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00125047